The overall objectives of this project are: (1) to quantitatively establish the relationships between sewage contamination and enteric virus levels in edible, bivalve, molluscan shellfish and the waters and sediments of their environment; (2) to quantitatively establish the major factors responsible for enteric virus movement, persistence and survival in shellfish and their habitat; and (3) to determine the optimum conditions for eliminating enteric viruses from shellfish by transferring them to unpolluted waters. The specific project aims are: (1) to quantitatively determine the amounts of enteric viruses in oysters and clams and the water and sediment in which they live as a function of distance from a point source discharge of treated sewage effluent into a coastal marine shellfish habitat; (2) to quantitatively determine the distribution, survival and fate of enteric viruses from a point source discharge of sewage effluent into a coastal marine shellfish habitat from specific information about: (a) virus levels in field samples, (b) virus persistence and survival in shellfish, water and sediment under field and laboratory conditions, and (c) hydrographic conditions in the shellfish habitat; (3) to establish the relationships, if any, between enteric viruses, bacterial pathogens and indicator bacteria in shellfish and in the water and sediment of their habitat; (4) to determine the kinetics of and the optimum environmental conditions for enteric virus elimination from sewage-contaminated shellfish that are transferred (relayed) to uncontaminated waters and to compare the rates and degrees of elimination to those for enteric bacteria and heavy metals.